On the process of BEM analysis, aerodynamic data must be
prepared for each blade element. It is well known that the
airfoil lift coefficient of a rotating blade has a greater value
than the predicted lift coefficient in 2-D or lift coefficient
without rotation. Therefore, the predicted results obtained
from BEMT based code do not reflect the 3-D rotating effects,
especially for inboard region of blades, and some errors are
inevitable [11].